History of the flight
The Lancair, registered VH-CIV, was a homebuilt aircraft operating under an experimental certificate of airworthiness. The owner had recently built the aircraft and had commenced a test flight program. The aircraft departed with a test pilot occupying the pilot seat, and the owner/builder occupying the right seat. Witnesses reported seeing the aircraft flying in the Drysdale area before descending steeply. It subsequently impacted the ground and the two occupants were fatally injured.
The pilot departed from Point Cook and flew along the coast, southwest of Point Cook aerodrome, at altitudes between 3,000 ft and 4,000 ft. After crossing Port Phillip Bay to the Bellarine Peninsula the pilot climbed the aircraft to between 5,000 ft and 6,000 ft. Recorded flight data indicated that the aircraft was slowed, and stalled at an altitude of 5,200 ft. The pilot recovered from the stall, but the aircraft entered another stall during the recovery at 4,950 ft. The pilot recovered the aircraft from that stall, and then repositioned it and entered a third stall at an altitude of 6,200 ft. The aircraft rolled at the initiation of the stall, and continued to roll as it then descended rapidly, accelerating to approximately 150 kts at an angle of approximately 40 degrees from the horizontal, with low engine power. The engine power increased shortly before the aircraft impacted the ground.
The aircraft impacted the ground upright, with the wings level, at a pitch angle of 40 degrees nose down. The landing gear was retracted at the time of impact, and the flaps were either completely or nearly retracted. There was no indication of any mechanical failure prior to impact. The accident was not survivable.
Flight crew
The pilot was an experienced ex-military pilot with 6,500 hours total aeronautical experience, including experience over many years in aircraft with a wide range of performances.
The owner/builder had a Commercial Pilot (Aeroplane) Licence issued 16 October 2001. He had 352 hours total aeronautical experience in a range of general aviation aircraft with a level of complexity and performance up to four-seat single-engine aircraft, with a constant speed propeller and retractable landing gear.
Aircraft
The aircraft was originally being constructed to comply with the requirements of Civil Aviation Safety Authority (CASA) Civil Aviation Order (CAO) 101.28. During construction, the experimental designation concept was developed and the aircraft construction was subsequently changed and completed in accordance with the experimental designation under Advisory Circular (AC) 21.4(2) issued September 2000. The certification requirements in the experimental category were less prescriptive than those in CAO 101.28 as experimental aircraft are not type-certificated. 'Experimental' is not a category but rather a designation. It is also important to note that an experimental certificate does not attest to an aircraft being fully airworthy (Civil Aviation Safety Authority Advisory Circular 21.1(1) - Aircraft Airworthiness Certification Categories and Designations Explained - Revised December 2000).
The aircraft was based on a Lancair IV-T kit plane that was originally designed to use a high-performance piston engine. The owner/builder decided to replace the engine with a turbo-propeller engine and sought assistance from a number of people to redesign the aircraft to accommodate the new engine.
Documentation indicated that during construction, numerous changes had been made to the original design, including the engine type and the design of the aircraft from the firewall forward. The propeller had been modified by removing 20 cm of the propeller tips. No evidence was found to indicate that any form of risk assessment had been undertaken to consider the safety implication of these aircraft design changes. A risk assessment was not required for aircraft constructed under the experimental designation.
Aircraft equipment
The aircraft was equipped with an integrated electronic flight information system (EFIS) comprised of a number of data acquisition units and three liquid crystal multi-function display (MFD) units, that could be configured to present operational information in different ways. The instrumentation system received data from a variety of sources, and integrated that data to present operational information to the pilot. Each MFD also contained a memory unit that recorded information that was sent to it. This information was used by the ATSB to determine the flight profile prior to the accident.
The MFDs could be selected by the pilot to display primary flight information, navigation information, or engine system information. The primary flight information consisted of an electronically generated artificial horizon display upon which a number of other information displays were overlayed. Indicated airspeed (IAS) was also displayed on the left side of this display. The IAS was presented as a vertical tape display of airspeed with a range of approximately 100 kts, in increments of 10 kts. The actual airspeed was also displayed numerically on the left side of the artificial horizon display, adjacent to the IAS speed tape display. The airspeed tape display contained a number of coloured regions to indicate various speed ranges and included the stall speed of the aircraft. The stall speed was dynamically generated and changed with varying flight loads on the aircraft. The displayed stall speed was known as the G-corrected stall speed. The EFIS derived the G-corrected stall speed from the aircraft's static 1G stall speed. The 1G stall speed had to be manually entered into the EFIS. The aircraft instrumentation system had been programmed with a 1G indicated stall speed of 69 kts with flaps and landing gear retracted.
The aircraft was also equipped with a video camera mounted on the ceiling just behind the two front seats, which was aimed at the instrument panel. This camera operated for some of the test flights, and some of the recordings were recovered from the camera after the accident.
The original aircraft design (with a piston engine) had a declared indicated stall speed of 84 mph, or 73 kts with flaps and landing gear retracted. The Comparative Aircraft Flight Efficiency (CAFE) foundation test flight of this version of the aircraft type recorded a stall speed of 78 kts with flaps and landing gear retracted. That test flight was conducted with a calibrated pitot/static boom, so the indicated airspeed would have been accurate in that instance. A theoretical aerodynamic calculation for the accident aircraft indicated a stall speed of 82 kts. Recorded information indicated that the aircraft stalled at 82 kts at the commencement of the accident sequence.
A flight path marker symbol, in the centre of the primary flight display, indicated the current pitch attitude of the aircraft. At an airspeed of 20 kts above the G-corrected stall speed, an amber pitch limit indicator symbol appeared above the flight path marker. The pitch limit indicator symbol moved down toward the flight path marker symbol as the airspeed decreased towards the stall speed. At 5 kts above the stall speed, the pitch limit indicator symbol turned red. At the point of stall, the pitch limit indicator symbol overlayed the flight path marker symbol. Coincident with the pitch limit indicator symbol changing to red, an aural annunciator would repeat a voice warning of 'stall' and a red stall flag symbol would display in the bottom left corner of the primary flight display.
The aircraft was also equipped with an angle of attack sensing device that used pressure information from two ports on the upper and lower sides of the left wingtip to derive the angle of attack. This instrument could have indicated when the aircraft was approaching a stall. The investigation did not determine if it had been calibrated before the accident flight.
During a test flight on 9 December 2002, the test pilot had decelerated the aircraft until it was approaching the stall as a part of the test flight program. Written records from that flight noted:
'A/c [aircraft] becomes laterally unstable below 80 Kts.'
Recorded flight data indicated that the aircraft stalled three times during this flight, from speeds of 72, 75 and 76 kts. The test pilot had also noted:
'Close to stall at 75 Kts with 10 [degrees] flap
Close to stall at 72 Kts with full flap'.
Video recordings from the flight indicated that the aircraft had stalled, and rolled 45 degrees to the left, and then 45 degrees to the right of horizontal during the recovery from the stall. Stalls were not a part of the test flight program for the flight.
Test program
A friend of the owner/builder developed a program for the flight testing of the aircraft. That program followed the guidelines in the Federal Aviation Administration (FAA) Advisory Circular 90-89A - Amateur-built Aircraft and Ultralight Test flighting Handbook. The CASA Advisory Circular 21.4(2) - Amateur Built Experimental Aircraft - Certification, advised that CASA:
'...most strongly urges [Amateur-built experimental aircraft builders] to make detailed reference to [this document], prior to their flight programs commencing, and [to] follow the guidance provided.' (section 14.4).
The test flight program was detailed, and was clearly developed in accordance with the recommendations of Advisory Circular 90-89A. Neither the advisory material, nor the test flight program considered action to be taken if aircraft handling or performance produced unexpected results.
CASA Advisory Circular 21.4(2) stated:
'14.5 Those undertaking test flight programs may also derive benefit in consulting the following additional references, as applicable to the class of aircraft involved:
'(a) CAA publication dated January 91, Flight Test Guide for Certification of CAO 101.28 Category Aeroplanes...'
This document recommended calibration of aircraft flight instruments, so that the limits of the flight envelope could be accurately determined. The test flight program for the accident aircraft did not include the in-flight calibration of aircraft flight instruments, including the airspeed indicator. Comparison of the recorded airspeed from the satellite navigation system, fitted to the aircraft as apart of the EFIS, with the recorded airspeed from the pitot/static system showed no inaccuracy in airspeed indication.
There was no evidence that any significant risk assessment was undertaken during construction of the aircraft and in the development of the test flight program. Such a risk assessment could have examined the planned activities and considered any potential hazards for their likely impact on the aircraft's safety during test flights.
The friend who developed the test program stated that he conducted the first two flights of the aircraft, but subsequently did not participate any further in the test program. Prior to those initial flights, he conducted an operational pre-flight briefing with the owner. These briefings included hazards and potential actions. The investigation did not determine whether the test pilot for the accident flight conducted similar operational pre-flight briefings for subsequent flights.
There was no evidence that any significant re-evaluation of risk was done during the subsequent conduct of the test flight program. Such a risk assessment process could have examined the results of test flights for hazards that became apparent from analysis of observations and data from each flight. This could have allowed for a considered assessment of any risk mitigators for their likely impact on the aircraft's safety during subsequent test flights, as the aircraft flight envelope was expanded. For example, if unexpected handling characteristics had been encountered during a stall sequence, then previously identified mitigation procedures, such as moving the centre of gravity forward, could have been considered.
Aircraft design
An aircraft operated as an experimental aircraft does not have to comply with any specific design. Builders may comply exactly with a design, or may deviate from that design as much as they wish, or may build an aircraft independent of any previously developed design.
If an aircraft is built mainly in accordance with an established design, but with some design differences, then it may perform differently from an aircraft built exactly in accordance with that established design. If design differences are incorporated one at a time, then it is possible to measure the effect of any single design difference. If many design differences are incorporated at one time, the effect of a single design difference on the behaviour of the aircraft may be impossible to predict due to the compounding effect of other incorporated design differences. The accident aircraft had been constructed with many differences compared with the original Lancair IV-T design.
Required persons on board during test flights
A CASA delegate had issued a special certificate of airworthiness authorising flight in accordance with the test flight program. The approval included operating limitations for the test flight program, such as geographical limitations, minimum weather conditions for flight and the maximum number of persons to be on board the aircraft.
Test flights are hazardous compared with normal flight. Accordingly, there is normally a requirement for only operational persons to be on board an aircraft during a test flight. The special certificate of airworthiness under which the accident flight was made stated 'Only personnel essential for the conduct of the testing may fly on board the aircraft. The carriage of passengers is prohibited.'
This aircraft type was normally flown as a single crew operation, and the cockpit of this aircraft was configured for single crew operation. There was no evidence that the test flighting required two persons on board.